[s-cars] 1/4 miles and clutches

[Aaron]

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FWIW this technique works real well for simple rolling start street
racing (1,2,3 go sort of thing)

If you are rolling with clutch out you can apply lots of throttle and
brake at the same time to get turbo spooling.  Then let go for rocket
launch.   The first time I tried this I was pleasantly surprised.
That pesky lag is reduced.
AT

Keith Maddock wrote:

>All this talk of 1/4 miles times and launches, I thought I'd share my OneL=
ap experience.
>
>We had two 1/4 mile drags in OneLap... I managed to botch both of em..
>Run 1: 14.936   (sorry no trap speed)
>Hmm can't find the time for Run 2 , but it was pretty similar maybe .1 or =
.2 sec faster.
>
>This was before Mark and I found that a much better launch can be had by h=
olding the parking brake pretty tight, revving up to about 3500-4000 rpm, s=
lowly letting out the clutch to put some load on the engine to get the boos=
t up, then releasing the parking break, and gradually letting the clutch ou=
t=2E  The key was to keep the RPM's and the boost up!  Needless to say this=
 procedure has two drawbacks:
>1) Hard to time for a 1/4 launch  (easy for a OneLap style launch where yo=
ur time starts when you pass the light-beam trigger 5 feet after your start=
 line...)
>2) Pretty hard on the clutch...
>
>Anyone have a better launch / clutch torture procedure?
>
>For comparison, some interesting OneLap 1/4 times:
>(remember lots of these drivers had never done a 1/4 drag before)
>Lister Vette: 11.255
>Viper ACR: 11.833     (one lap winner)
>Supra TT: 12.193     (definately far from stock)
>996TT: 12.346     (stock i think..)
>Plymouth Valiant: 12.507
>Z06 Vette: 12.914    (stock i think..)
>V8 280z: 13.166     (go datsun!)
>Renntech C32 AMG: 13.362    (~400hp)
>Shogun: 13.651     (Festiva with rear moutned supercharged SHO engine)
>M5: 13.821     (supercharged)
>APR modd'd S4tt: 14.161     (supposedly ~310-320 hp)
>Stock S4tt: 14.262
>MTM modd'd S4tt: 14.567    (supposedly ~360 hp)
>jag S Type R: 14.488    (stock)
>
>Keith "Car-less in Koblenz" Maddock
>93 S4 with goodies, but 7000 miles away
>
>
>****************************************************************
>Keith Maddock, TRW Automotive,  Koblenz, Germany
>Slip Control Systems, Systems Design, Traction Control
>+49 (0)261/ 895 2474     -    -    keith.maddock at trw.com
>
>>>>"Jack Gagnon" <bullitt at cybertours.com> 21-Aug-02 04:13:12 >>>
>>>>
>
>Yea Paul is right
>
>How about this
>Me
>
>Run 1 :20.423 at 64.90 (yup that is 20 seconds).
>Run 2: 18.065 at 81.44
>Run 3: 21.401 at 65.11(limp mode again)
>
>Pretty pathetic huh! I am used to running 12.8's@ 110 with my 89 mustang
>
>other lane
>
>Run 1 :12.828 at 104.76 1.8 60' (60's GM muscle car)
>Run 2: 13.619 at 100.98 2.0 60' ( Ford Lighting Pickup)
>Run 3: 14.365 at 100.46 2.3 60' (BMW M3)
>
>
>Explanation/Excuses
>
>1.	I just swapped out my tiny undersized puny TAP injectors with stock
>injectors and did not disable the Rising rate FPR resulting in way rich
>conditions.
>
>2.	The ECU detected an overboost condition (Code 224)and I hit the fuel cut
>out in 1st gear. the remainder of the run was in low boost limp mode.  Runs
>1& 3 I hit the fuel cut out, Run 2 Was sputtering from the rich condition
>and I short shifted to keep the damn thing from going into limp mode again.
>
>3.	I was Fr#$#@n HOT! 97deg and 10 minutes of heat soak prior to each run.
>
>I have since corrected my overboost problem (bad MAF sensor connection) and
>removed the rising rate FPR and everything is running fine now.  I did a f=
ew
>0-60 runs with the g-tech and was able to get a 5.9 without a miss so I am
>ready to race again!  I even managed to get a bit of clutch smell while
>trying to perfect my launch.  It appears that dropping the clutch at much
>over 3500 rpm results in enough engine power to get no bog, but the damn c=
ar
>is so heavy that the clutch slips.  Even though the times really sucked I
>learned that my car needed some TLC and the trip was worth it.  I think I
>will try again soon.
>
>
>92 S4
>K& N Cone filter
>KKK small 26/Garrett T04 turbo
>Sport intercooler
>Piper cams
>Ported heads
>RS2 EM
>3" exhaust
>Lehmann stage 3 chip
>3 bar sensor
>Big reds
>Koni's
>245/40 17's
>
>What do you think it will run?
>
>Jack G
>
>
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